Spectral Shaping Device for Semiconductor Optical Characterization

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Solution Overview

Problem

Existing optical inspection methods for semiconductor substrates face challenges in achieving precise quality control due to non-uniform spectral emission from light sources and varying attenuation of spectral components along the optical path, leading to oversaturation of detectors and inaccurate characterization.

Innovation Solution

The implementation of spatial or temporal separation of light beams into spectral components, followed by controlled intensity adjustment using dispersive optical devices and dynamic filters, to achieve a desired spectral profile that ensures accurate and reliable reflectometry and ellipsometry measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If broadband light sources are used to provide wide spectral range for optical characterization, then the spectral coverage is improved, but the non-uniform emission and varying attenuation cause detector oversaturation and measurement inaccuracy

Engineering Contradiction:

Improvespectral coverageVSAvoidmeasurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The broadband light beam is segmented into multiple spectral components using dispersive optical elements (prisms, diffraction gratings). Each spectral component is then independently controlled through dynamically adjustable filters or aperture masks, allowing precise regulation of intensity for each wavelength range to prevent detector oversaturation while maintaining comprehensive spectral coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system employs dynamic filters or aperture masks with adjustable transmission characteristics that can be modified in real-time. This dynamic control allows the system to adapt the intensity of each spectral component based on the specific measurement requirements, preventing oversaturation while ensuring adequate signal strength across the entire spectral range.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If certain spectral components are enhanced to improve characterization accuracy, then the measurement precision is improved, but the overall spectral uniformity deteriorates

Engineering Contradiction:

Improvecharacterization accuracyVSAvoidspectral uniformity

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The system applies different transmission characteristics to different spectral components through dynamically adjustable filters or aperture masks. This allows each spectral component to be locally optimized for its specific measurement requirements, enhancing the precision of characterization for particular wavelength ranges while maintaining controlled intensity distribution across the full spectrum.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If spectral components are separated and individually controlled, then the spectral profile control is improved, but the device complexity increases

Engineering Contradiction:

Improvespectral profile controlVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system uses a single broadband light source that provides the entire spectral range, eliminating the need for multiple light sources. Dispersive optical elements separate the spectrum, and dynamically adjustable filters or aperture masks provide universal control over all spectral components through a unified mechanism, reducing overall system complexity while maintaining precise spectral profile control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables more accurate and reliable characterization of semiconductor manufacturing outputs by enhancing the presence of underrepresented spectral components, such as IR and UV, thereby improving the quality control of substrates during manufacturing.

Implementation Method 1

spatial or temporal separation of light beams into spectral components

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

controlled intensity adjustment using dispersive optical devices and dynamic filters

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS11226234B2Spectrum shaping devices and techniques for optical characterization applications

Publication Date: 2022.01.18 APPLIED MATERIALS INC

AI summary

Implementations disclosed describe a system comprising a first optical device to receive an input beam of light, the input beam having a plurality of spectral components of light, and cause the input beam to disperse into a plurality of spectral beams, wherein each of the plurality of spectral beams corresponds to one of the plurality of spectral components and propagates along a spatial path that is different from spatial paths of other spectral beams, and a second optical device to collect a portion of each of the spectral beams, wherein the collected portion depends on the spatial path of the respective spectral beam, and form an output beam of light from the collected portion of each of the spectral beams, wherein a spectral profile of the output beam is different from a spectral profile of the input beam of light.